SFP GLC-T and SFP GE-T are both types of small form-factor pluggable (SFP) transceivers, but they are designed for different types of network connections.

SFP GLC-T is a copper transceiver that supports Gigabit Ethernet (GE) over twisted pair copper cabling, typically with an RJ45 connector. It is commonly used for connecting network devices such as switches, routers, and servers to copper-based Ethernet networks.

On the other hand, SFP GE-T is also a copper transceiver that supports Gigabit Ethernet over twisted pair copper cabling. However, it is specifically designed for Cisco networking equipment and may have compatibility limitations with other devices.

In summary, while both SFP GLC-T and SFP GE-T are copper transceivers for Gigabit Ethernet, SFP GLC-T is more widely compatible with various network devices, while SFP GE-T is specifically designed for use with Cisco equipment.